This invention relates to methods of promoting the growth of plants and in particular it relates to methods for increasing the yield of fruit production of plants. In another aspect, the invention relates to increasing the rate of growth of legumes and yields of edible reproductive fruits of said legumes. In still another aspect, the application of effective amount of the vanadyl compositions applied to plants during growth cycles has been found to promote plant growth and plant fruit yield in peanuts, a legume.
Worldwide increasing population increases demands on horticulture efficiency and agricultural crop yields from all sources. The need to improve these efficiencies and yields is ever present especially in view of the loss of productive farm land. Thus, improved plant growth and plant fruit yields and quality are needed along with better utilization of agricultural lands in order to meet the increasing population growth food requirements. Plant growth regulators which can economize the use of fertilizers, nutrients, enzymes, and other growth promoters for various plants are being investigated continuously. Unfortunately, plant growth regulators and specific species of plants along with different generic classes of plants provides the researcher with less than predictable results even when utilizing same or similar compounds successfully applied to other species and generic classes.
Plant growth regulators can be defined as compounds and preparation which in minute amounts alter the behavior of crop plants or the produce of such plants through physiological (hormonal) tendencies rather than physical action. Plant growth regulators may either accelerate or retard growth, prolong or break a dormant condition, promoting rooting, fruit-set, or increase fruit size or quantity, or effect a growth and or productivity of plants in other ways. Plant growth regulation activity can vary from plant to plant as well as from novel composition to novel composition and specific combinations of the compositions and plants.
Various compositions have been studied as micro nutrients and plant growth promoters to increase crop productivity across a wide range of horticulture and agricultural crops. Compositions which include vanadium compounds have been studied and have results both beneficial and detrimental in effect on plants. Vanadium occurs in higher plants at levels usually between 0.2 and 4 ppm. Studies indicate that vanadium may have some effect on plants, including higher order plants which are of agricultural interest. Whether that effect is beneficial or detrimental appears to depend on the form of the vanadium, the type of plant and the method and timing of the application.
The importance of many metallic elements as integral constituents of enzymes and electron carriers warrants the attention of many plant physiologists. Aside from their roles as cofactors, activators are regulators in many enzymes' reactions, trace elements are essential to the maintenance of many biochemical processes in plants. Vanadium is one of the trace elements that is widely distributed in plants. Despite the fact that has been shown that vanadium increases growth in lettuce, tomatoes, asparagus, corn, barley and rice and the like, there is still no conclusive evidence that it is an essential element for higher plants. It does not meet the criteria of essentiality to the plant. However, vanadium on the other hand appears to be essential for many microorganisms. Continuing studies are being undertaken presently as they have in the past to investigate the distribution of vanadium and its effects on growth of agriculturally useful plants. Vanadium has stimulated growth and mazed plants at levels of 0.25 ppm in nutrient solutions. However, vanadium had no effect on lettuce or tomato plants at levels of 0.05 ppm. Lauchili et al. 15B ENCYCLOPEDIA OF PLANT PHYSIOLOGY 723-26 (1983). A study of the effect of a foliar spray of a vanadyl sulfate solution on leaf growth of sugar beet plants indicated that it decreased leaf growth, but that it increased the amount of reducing sugar in the roots of the sugar beet. Singh et al. 44 PLANT PHYSIOLOGY 1321-27 (1969). The use of vanadium (in the form of vanadyl lactate at concentrations of 10.sup.-3 to 10.sup.-6 molar) as a fertilizer has produced an increase in foliage yield of some higher plants. Kerr et al. Monograph 11 BRITISH PLANT GROWTH REGULATOR GROUP 103-21 (1984).
More recently vanadyl composition have been used in promoting the lint yield of fiber producing plants such as cotton by heating the plant during growth periods of the plant with an amount of a vanadyl salt of a carboxycilic acid. These compositions are found in U.S. Pat. No. 5,186,738 hereby incorporated by reference; however the '738 patent reports that the vanadyl composition proved ineffective for promoting the growth of soybeans, a legume. Again illustrating the variations of experience with vanadyl compositions in achieving regulation activity ie. plant growth and plant fruit growth enhancement from plant to plant. Thus, a continuing need exists for development of effective vanadium composition methods, timing and conditions of application in order to achieve enchanced edible fruit production.